Aerosol-generating device with reduced leakage

ABSTRACT

An aerosol-generating device includes a housing having a first end defining a mouthpiece, a second end, and a cavity defined between the first end and the second end. The device also includes a reservoir within the cavity. The reservoir is configured to store a liquid aerosol-forming substrate. The device also includes an atomizer and a valve within the mouthpiece of the housing. The valve has a first side and an second side. The second side of the valve includes a hydrophilic coating, a hydrophobic coating, or both a hydrophilic coating and a hydrophobic coating.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of, and claims priority to,international application no. PCT/EP2018/085491, filed on Dec. 18, 2018,and further claims priority under 35 U.S.C. § 119 to European PatentApplication No. 18154263.0, filed Jan. 30, 2018, the entire contents ofeach of which are incorporated herein by reference.

BACKGROUND Field

Example embodiments relate to an aerosol-generating device configured toheat an aerosol-forming substrate to form an inhalable aerosol. Exampleembodiments relate to an aerosol-generating device that is configured toreduce and/or minimize leaking of liquid aerosol-forming substrate orcondensates.

Description of Related Art

Devices for generating aerosols for inhalation heat a liquid to vaporizethe liquid and produce an aerosol. Such devices typically include aliquid storage portion or reservoir for holding a supply of a liquidaerosol-forming substrate, or “e-liquid”, and a heater for heating thee-liquid to generate an aerosol. Such devices also include an airflowpath in communication with the heater so that the aerosol can beconveyed along the airflow path and delivered to a user.

The quality of the aerosol generated by known devices can be assessedusing a number of different factors. Factors may include the quantity ofaerosol generated, the density of droplets within the aerosol,temperature of the aerosol, and speed of delivery of the aerosol. Thequality of the experience provided by known devices may be assessedusing a number of different factors. These factors may include thequality of aerosol generated as well as frequency of liquid leaking fromthe device.

Liquid leaking from an aerosol generating device could be e-liquidleaking from the reservoir itself. Liquid leaking from a device may bee-liquid that was incident on the heater but was not vaporized by theheater. Liquid that has been vaporized by the heater may condense withinthe device and form large droplets that then leak from the device. Inparticular, large droplets may form when the hot air and vapour from theheater meet the cooler internal surfaces of the device housing.

SUMMARY

At least one example embodiment relates to an aerosol-generating device.

In at least one example embodiment, an aerosol-generating device mayinclude a housing, a reservoir, an atomizer, and a valve. The housingmay include a first end defining a mouthpiece, a second end, and acavity between the first end and the second end. The reservoir may bewithin the cavity and may be configured to store an aerosol-formingsubstrate. The valve may be within the mouthpiece of the housing. Thevalve may include a first side and a second side. The second side of thevalve may include a hydrophilic coating, a hydrophobic coating, or botha hydrophilic coating and a hydrophobic coating.

In at least one example embodiment, the aerosol-generating devicefurther includes an air inlet in the housing and an airflow channel. Theairflow channel may extend from the air inlet, through the cavity, andto the mouthpiece. The valve may be in the airflow channel. The airflowchannel may pass the atomizer.

In at least one example embodiment, the valve is a one-way valve. Thevalve may be configured to reduce the aerosol-forming substrate passingfrom the second side of the valve to the first side of the valve. Thevalve may include a hydrophobic coating.

In at least one example embodiment, the aerosol-generating device mayfurther includes a storage tank configured to receive a portion of theaerosol-forming substrate repelled by the hydrophobic material of thecoating of the valve.

In at least one example embodiment, the valve may be a ball valve, aduckbill valve, a diaphragm, an umbrella valve, or a hinged flap. Thevalve may be actuated via a draw on the mouthpiece of theaerosol-generating device. The valve may be actuated via a button on thehousing. The valve may be at or near the first end of the housing andwithin the mouthpiece.

In at least one example embodiment, the atomizer includes a heater. Theheater may include at least one heating element. The heater may be incommunication with a wick. The wick may be configured to direct theaerosol-forming substrate from the reservoir to the at least one heatingelement.

In at least one example embodiment, the aerosol-generating device mayfurther include a director configured to direct liquid resulting fromcondensation of aerosolized aerosol-forming substrate towards the atleast one heating element.

In at least one example embodiment, the reservoir comprises an outerwall including a first face and a second face. The first face may beexposed to an airflow channel. The first face may be formed ofhydrophobic material. The second face may be opposite the first face.The second face may be formed of a hydrophilic material. The outer wallmay be in the airflow channel downstream of the atomizer.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments will now be described, by way of example only, withreference to the accompanying drawings.

FIG. 1 is a perspective view of an aerosol-generating device accordingto at least one example embodiment.

FIGS. 2A to 2E are views of an aerosol-generating device according to atleast one example embodiment.

FIGS. 3A to 3G are views of an aerosol-generating device according to atleast one example embodiment including an umbrella valve.

FIGS. 4A to 4E are views of an aerosol-generating device according to atleast one example embodiment including a ball valve.

FIGS. 5A to 5C show layers applied to the walls of an airflow passagewithin an aerosol-generating device according to at least one exampleembodiment.

DETAILED DESCRIPTION

In at least one example embodiment, an aerosol-generating devicecomprises a housing having a first end defining a mouthpiece, a secondend and a cavity defined between the first end and the second end. Thedevice also comprises a reservoir within the cavity, for storing aliquid aerosol-forming substrate, and an atomizer. The device furthercomprises a valve within the mouthpiece of the housing, the valve havinga downstream (or first) side and an upstream (or second) side. Thesecond side of the valve includes one or more of a hydrophilic coating,a hydrophobic coating or a liquid absorbent coating.

The device may comprise an air inlet in the housing and an airflowchannel from the air inlet, through the cavity to the mouthpiece. Thevalve may be in the airflow channel. The airflow channel may pass theatomizer. Atomized liquid may be entrained within an airflow passingthrough the airflow channel.

As used herein, ‘aerosol-generating device’ relates to a device thatinteracts with an aerosol-forming substrate or an aerosol-generatingarticle to generate an aerosol. An aerosol-generating device maycomprise one or more devices used to supply energy from a power supplyto an aerosol-forming substrate or an aerosol-generating article togenerate an aerosol. An aerosol-generating device may comprise a powersupply which may be an external power supply or an on-board power supplyforming part of the aerosol-generating device. An aerosol-generatingdevice may interact with an aerosol-forming substrate or anaerosol-generating article to generate an aerosol.

As used herein, the term ‘aerosol-forming substrate’ relates to asubstrate capable of releasing volatile compounds that can form anaerosol. The volatile compounds may be released by heating theaerosol-forming substrate. The aerosol-forming substrate may beadsorbed, coated, impregnated or otherwise loaded onto a carrier orsupport. A suitable aerosol-forming substrate may comprise nicotine, aplant-based material, a homogenised plant-based material, at least oneaerosol-former or other additives or ingredients, such as flavorants.

As used herein, ‘downstream’ is used to describe the relative positionportions of the aerosol-generating device in relation to the directionof air flow through the device. The downstream (first) side of the valvemay be closest to the mouthpiece in the direction of airflow and theupstream (second) side of the valve may be closest to the atomizer inthe direction of airflow. In other words, air from the atomizer may beincident on the upstream side of the valve and air from the downstreamside of the valve may be drawn through the mouthpiece. Theaerosol-generating article may comprise a proximal end through whichgenerated aerosol exits the aerosol-generating device. The proximal endmay also be referred to as the mouthpiece end. The aerosol-generatingdevice may be an elongate device, comprising a distal end opposite theproximal or mouth end. In such embodiments, the proximal end may bereferred to as the downstream end. Similarly, as used herein, ‘upstream’is used to describe the relative position of components, or portions ofcomponents, of the aerosol-generating device at the distal end of theaerosol-generating device.

As used herein, ‘length’ refers to the maximum longitudinal dimensionbetween the upstream (second) end, in this case the base or closed end,of the device and the downstream (first) end or mouthpiece of thedevice.

The reservoir may be fixed within the housing of the aerosol-generatingdevice. The reservoir may be refillable to allow for repeated vaping. Inat least one example embodiment including a refillable reservoir, thehousing of the aerosol-generating device may include an openingconfigured to allow aerosol-forming substrate to be inserted through theopening into the reservoir. Alternatively, the reservoir may beremovable from the housing of the aerosol-generating device. A removablereservoir may be refilled once it has been removed from the housing.Alternatively, the removable reservoir may be a single use reservoirthat is disposed of after depletion of the aerosol-forming substrate. Anew reservoir may subsequently be inserted into the aerosol-generatingdevice.

In at least one example embodiment, the reservoir is in fluidcommunication with the atomizer. The aerosol-forming substrate may betransported from the reservoir to the atomizer to be atomized. Transportmay be provided by a wick or capillary element extending between thereservoir and the atomizer. The aerosol-forming substrate may beentrained in an airflow in the airflow channel to form an aerosol.

The valve may control the flow of fluid out of the aerosol-generatingdevice. In at least one example embodiment, the valve reduces and/orprevents the exit of aerosol-forming substrate from theaerosol-generating device while allowing generated aerosol to exit viathe mouthpiece.

A coating on the valve may further reduce the flow of large droplets ofliquid through the valve. A coating may additionally, or alternatively,be provided on an downstream side of the valve, at the proximal end ofthe aerosol-generating device. The coating may be a hydrophilic coating,a hydrophobic coating, a liquid absorbent coating, a sub-combinationthereof, or a combination thereof.

Liquid incident on a hydrophobic coating may be repelled. Having ahydrophobic coating on the upstream (second) side of the valve may repelliquid from the valve and the liquid may be retained within the housingof the aerosol-generating device. In this manner, liquid condensingwithin the housing and forming large droplets may be reduced and/orprevented from leaking through the valve. The hydrophobic coating may beat least partially formed of either polyurethane (PU) or asuper-hydrophobic metal layer such as a micropore or mesh metal, such ascopper or aluminium, functionalized with carbon chains to make themsuper-hydrophobic.

Liquid incident on a hydrophilic coating may be attracted to thecoating. The coating may be on either an upstream (second) or downstream(first) side of the valve. A hydrophilic coating may attract liquid inthe vicinity of the valve and reduce and/or prevent large droplets ofliquid flowing through the valve or out of the device. The hydrophiliccoating may be at least partially formed of 3 polyamide, polyvinylacetate, cellulose acetate, cotton, a sub-combination thereof, or acombination thereof.

Liquid incident on a liquid absorbent coating may be absorbed into thecoating. The coating may be on either an upstream (second) or downstream(first) side of the valve. Absorbing liquid into the coating may storeliquid within the coating and reduce and/or prevent large droplets ofliquid flowing out of the valve. The liquid absorbent coating may be atleast partially formed of Nylon (polyamide), cellulose acetate, cottoncellulose, a sub-combination thereof, or a combination thereof.

Any combination of the hydrophobic, hydrophilic, and liquid absorbentcoatings may be used.

In at least one example embodiment, the valve is a one-way valveconfigured to reduce and/or inhibit the flow of large droplets of liquidfrom the upstream (second) side of the valve to the downstream (first)side of the valve. The one-way valve, together with one or morecoatings, may be configured to allow aerosol to move through the valve,while reducing and/or preventing large droplets of liquid from flowingout of the aerosol-generating device.

In some example embodiments, the valve includes a hydrophobic coatingand the aerosol-generating device further comprises a storage tank. Thestorage tank may be configured to receive liquid repelled by thehydrophobic coating. In at least one example embodiment, liquid that hasbeen repelled by the hydrophobic coating may be stored in the storagetank. The aerosol-generating device may further comprise a wick or acapillary element that is configured to direct liquid from thehydrophobic coating to the storage tank. The storage tank may bepositioned within the housing of the aerosol-generating device. Thestorage tank may be fixed within the housing of the aerosol-generatingdevice, and the housing may comprise an opening through which thestorage tank can be emptied. Alternatively, the storage tank may beremovable from the housing of the aerosol-generating device. Theremovable storage tank may be emptied once removed from the housing,such that it can be re-inserted into the housing and re-used.Alternatively, the removable storage tank may be disposable once removedfrom the housing. A new storage tank may then be inserted into thehousing. The storage tank may be in fluid communication with thereservoir to allow liquid in the storage tank to return to reservoir foratomizing again.

The valve may be a ball valve. Alternatively, the valve may be aduckbill valve. Alternatively, the valve may be a diaphragm valve.Alternatively, the valve may be an umbrella valve. Alternatively, thevalve may be a hinged flap. The valve may be any suitable one-way valve.A duckbill valve or an umbrella valve may be included.

In at least one example embodiment, the valve is actuated by a draw onthe mouthpiece of the aerosol-generating device. Actuation of the valvemay result in the valve opening such that fluid can flow from inside thehousing of the aerosol-generating device out through the mouthpiece ofthe aerosol-generating device. Actuation as a result of a draw providesa device that is simple to operate because no additional actions arerequired. Actuation as a result of a draw may ensure that aerosol canpass through the valve. Actuation as a result of a draw may ensure thatthe valve remains in the closed position when the aerosol-generatingdevice is not in use, such that liquid cannot escape through the valvewhen the aerosol-generating device is not in use.

Alternatively, or in addition, the valve may be actuated via a button onthe housing. In this alternative embodiment, the valve is mechanicallyactuated. A mechanically actuated valve may provide a feeling of greatercontrol when using the aerosol-generating device. A mechanicallyactuated valve may require manual actuation at the same time as a drawis initiated on the aerosol-generating device in order for generatedaerosol to flow out of the device. The button may be located on a sideof the housing of the aerosol-generating device, or on an end of thehousing of the aerosol-generating device. The button to actuate thevalve may be pressed simultaneous to a draw on the mouthpiece of theaerosol-generating device.

Alternatively, or in addition, the valve may be actuated by electricalsignals. The electrical signals may be generated by a flow sensorpositioned within the housing of the device and configured to detect adraw on the mouthpiece of the device. The flow sensor may be positioneddownstream of the valve. The housing may include a bypass flow channelin which the flow sensor is located.

In at least one example embodiment, the valve is positioned at or nearthe proximal end of the housing. In at least one example embodiment, thevalve is positioned within the mouthpiece. Providing a valve in themouthpiece of the aerosol-generating device may allow the valve toreduce and/or minimize leakage of both liquid that has leaked from thereservoir and liquid produced by condensation upstream of the atomizerin the housing of the aerosol-generating device. Minimizing and/orreducing the length of housing positioned downstream of the valve mayalso reduce and/or minimize the space in which aerosol can furthercondense to form liquid.

In at least one example embodiment, the atomizer may comprise a heater.A heater may vaporize liquid aerosol-forming substrate to form a vapour.The vapour may cool to form condensed liquid droplets within theairflow, forming an aerosol. Alternatively, the atomizer may be amechanical atomizer, including a piezoelectric element. In thisalternative embodiment, the piezoelectric element may vibrate inresponse to an alternating current being passed through thepiezoelectric element. Vibrations of the piezoelectric element may forcethe liquid aerosol-forming substrate through a nozzle assembly such thatdroplets of the liquid aerosol-forming substrate are formed. Thedroplets are entrained in the airflow in the airflow channel to form anaerosol.

In at least one example embodiment, the heater may comprise one or moreheating elements. The heating element may be a planar heating element, aheater rod, a heater coil, or any other suitable heating elementconfiguration. The heating element may be formed of an electricallyresistive material such that passing an electric current through theheating element causes the heating element to produce heat. The heatingelement may be directly electrically coupled to a heat source. Suitableelectrically resistive materials include semiconductors such as dopedceramics, for example doped silicon carbides, electrically ‘conductive’ceramics such as molybdenum disilicide, carbon, graphite, metals, metalalloys, and composite materials made of a ceramic material and a metalmaterial. Alternatively, or in addition, the heating element maycomprise a susceptor and the heater may further comprise an inductorlocated to induce a current to heat the susceptor. For example, theinductor may comprise a coil arranged outside a heating chamber, orsurrounding a heating chamber, that acts to induce heating currents inthe susceptor.

The heater may be in communication with a wick. The wick may beconfigured to direct liquid from the reservoir to the heater. The wickmay direct liquid aerosol-forming substrate from the reservoir to theheater. The wick may be at least partially formed of a material able toabsorb liquid aerosol-forming substrate. Such a material may be aporous, fibrous, spongy, foam or capillary material. The wick maycomprise a bundle of capillaries. The wick may comprise a plurality offibers. The wick may comprise fine-bore tubes. The wick may comprise acombination of fibers, threads and fine-bore tubes. The fibers, threadand fine-bore tubes may be generally aligned to convey liquid to theelectric heater. Such a material may have a desired (or, alternatively,pre-defined) capillarity. Examples of suitable materials to absorbliquid aerosol-forming substrate include ceramic- or graphite-basedmaterials in the form of fibers or sintered powders. Examples ofsuitable materials also include sponge or foam materials, foamed metalor plastics materials, a fibrous material, for example made of spun orextruded fibers, such as cellulose acetate, polyester, or bondedpolyolefin, polyethylene, terylene or polypropylene fibers, nylon fibersor ceramic.

Wicks of different porosities may be used to accommodate differentliquid physical properties such as density, viscosity, surface tensionand vapour pressure. The wick may have a first end positioned within thereservoir and a second end terminating at the heater. Alternatively, thesecond end of the wick may be surrounded by the heater. For example, ifthe heating element is a coil heating element then the coil may bewrapped around the second end of the wick. The second end of the wick istypically positioned within an airflow path within the housing of theaerosol-generating device so that air is drawn past the wick andentrains the vapor. The vapor may subsequently cool to form an aerosoland/or vapor.

In at least one example embodiment, the aerosol-generating system mayalso include a director configured to direct liquid resulting fromcondensation of aerosolised liquid aerosol-forming substrate towards theheater. The director may be positioned within the housing of the device.The director may be positioned external to each of the reservoir and theatomizer. The director may be a wicking member or a capillary element orany device configured to transport liquid to the atomizer. Directing theliquid to the atomizer may allow the liquid to be aerosolized orre-aerosolized, so that accumulation within the housing may be reduced.

In at least one example embodiment, the reservoir of theaerosol-generating device comprises an outer wall having a first faceexposed to the airflow channel in the housing and formed of hydrophobicmaterial. The reservoir may further comprise a second face opposite thefirst face and formed of a hydrophilic material. The outer wall of thereservoir may be positioned adjacent the airflow channel downstream ofthe atomizer. With this arrangement liquid condensed on the outer wallmay be transported into the reservoir through the outer wall, andescaping of liquid in the reservoir via the outer wall may be reduced.

The airflow channel downstream of the atomizer may comprise walls havinga first layer, in contact with aerosol in the airflow channel,comprising a hydrophobic material and a second layer, underneath thefirst layer, comprising a hydrophilic material.

In at least one example embodiment, the aerosol-generating system mayfurther comprise a power supply and a control unit. The power supply mayprovide power to the heater. The heater is configured to heat anaerosol-forming substrate. With this arrangement an aerosol can begenerated. The control unit may control the power supplied from thepower supply to the heater. The control unit may control the temperaturegenerated and the duration of the heating. The control unit may controlother characteristics of the heater.

FIG. 1 is a schematic representation of an aerosol-generating device 10.The aerosol-generating device 10 comprises a housing 12 with a distalend 14 and a proximal end 16. The housing 12 at the proximal end 16narrows to define a mouthpiece 18. Within the housing 12 is a powersupply 21, a control unit 20, a reservoir of liquid aerosol-formingsubstrate 22, an atomizer 24, and a valve 26. An air flow channel 25 isdefined within the housing 12, such that air can be drawn through thehousing 12 from an air inlet 23 to the mouthpiece 18 and through thevalve 26. A draw on the mouthpiece 18 draws air through the air inlet 23and through or past the atomizer 24 such that aerosolized droplets ofthe aerosol-forming substrate 22 are entrained in the air flow. The airflow then passes out of the valve 26 and through the mouthpiece.

The power supply 21 and the control unit 20 may be contained in areusable portion of the device 10, and the atomizer 24, the reservoir22, and the mouthpiece 18 may be part of a consumable portion of thedevice 10 that is attached to the reusable portion.

FIGS. 2A to 2E are illustrations of at least one example embodiment ofan aerosol-generating device 10. The valve 26 shown in FIG. 2A is aduckbill valve. As shown, a proximal end 16 of the mouthpiece 18 of thehousing 12 is covered by a valve connector 28. The valve connector 28has a distal open end 30 and a proximal closed end 32 as shown in FIG.2B. The open end 30 is shaped to slide over the proximal end 16 of thehousing 12 and be retained in position covering the proximal end 16. Theclosed end 32 includes an aperture 34. The duckbill valve 26 is locatedwithin the aperture 34 of the valve connector 28.

FIG. 2C shows the duckbill valve 26 alone. The duckbill valve 26comprises a valve seat 36 and a nozzle 38. A channel 42, shown in FIG.2D, runs through the nozzle 38, defined by inner walls 50 of the nozzle.The channel 42 extends from an opening 44 in the valve seat 36 to anopening 46, shown in FIG. 2D, in the nozzle 38 defined by opposing sides40 and 40′, shown in FIG. 2C. When in position, the channel 42 of theduckbill valve 26 aligns with the air flow channel 25 of the device 10as shown in the cut through views of FIGS. 2D and 2E.

The nozzle 38 may be formed of a rubber or elastomer material such thatthe nozzle 38 is deformable. The nozzle 38 is shaped such that when noforce is applied to the nozzle 38, opposing sides 40 and 40′ of thenozzle 38 are in contact and the opening 46 of the nozzle is in a closedposition. In the closed position, the opposing sides 40 and 40′ of thenozzle 38 reduce and/or prevent liquid such as e-liquid or condensedaerosol escaping through the valve 26 when there is no draw on thedevice. When air is drawn through the channel 42 from the valve seat 36to the nozzle 38, air pressure inside the nozzle 38 forces the opposingsides 40 and 40′ apart, such that air can escape through the opening 44.

The duckbill valve 26 includes an inner coating 48, shown in FIG. 2E.The inner coating 48 is a hydrophobic coating. The coating 48 coverssubstantially the entirely of the inner wall 50 of the nozzle 38. Thecoating 48 repels liquid, such as e-liquid or condensed aerosol. When adraw is initiated on the device 10 and the nozzle 38 is brought into theopen position, liquid is reduced and/or prevented from escaping throughthe opening 46 as the coating 48 repels the liquid so that the liquidcannot pass through the nozzle 38. In this way, the coating 48 reducesand/or prevents liquid leaking from the mouthpiece 18.

FIGS. 3A to 3G illustrate at least one example embodiment of anaerosol-generating device 10. The valve 26 may be an umbrella valve. Inat least one example embodiment, a proximal end 16 of the mouthpiece 18of the housing 12 is covered by a valve connector 28. Again, otherexample embodiments, the valve connector 28 shown in FIGS. 3A to 3G hasa distal open end 30 and a proximal closed end 32. The open end 30 isshaped to slide over the proximal end 16 of the mouthpiece 18 and beretained in position covering the proximal end 16. In at least oneexample embodiment, the closed end 32 includes a central aperture 54 andtwo side apertures 56 and 56′ shown in FIG. 3G. The side apertures 56and 56′ are coaxial with the air channel 25 of the device 10 as shown inthe cut through views of FIGS. 3D and 3E.

FIG. 3C illustrates the umbrella valve 52 alone. The umbrella valve 52comprises a valve plug 58, a valve neck 60 and an umbrella portion 62.The valve neck 60 runs between the valve plug 58 and the umbrellaportion 62. The valve neck 56 is positioned within the central aperture54 of the closed end 32 of the valve connector 28. The valve plug 58 islocated on an upstream side of the closed end 32. The umbrella portion62 is located opposite the valve plug 58 on a downstream side of theclosed end 32. The umbrella portion 62 is a concave circular portion,extending downwards from the end of the valve neck 60 towards the valveplug 58.

The valve plug 58 has an external circumference larger than the internalcircumference of the central aperture 54. Therefore, the valve plug 58is prevented from passing through the central aperture 54.

The umbrella portion 62 has an external circumference such that itextends over each of the side apertures 56 and 56′ in a closed positionas shown in FIG. 3F. In the closed position, escape of liquid is throughthe valve 26 when there is no draw on the device 10 is reduced and/orprevented. The umbrella portion 62 is formed of a rubber or elastomermaterial such that the umbrella portion 62 is deformable. When air isdrawn through the device 10, air pressure on the upstream side of theumbrella portion 62 from air passing through the side apertures 56 and56′ forces the umbrella portion 62 to deform and invert, such that theumbrella portion 62 no longer covers the side apertures 56 and 56′ suchthat air can pass through the valve 26 as shown in FIG. 3G.

The umbrella valve 52 includes an inner coating 64, shown in FIGS. 3Fand 3G. The inner coating 64 may be a hydrophobic coating. The coating64 is located both on the upstream side of the closed end 32 and on theupstream side of the umbrella portion 62. The coating 64 repels liquid,such as e-liquid or condensed aerosol. When a draw is taken on thedevice 10 and the umbrella portion 62 is inverted such that the sideapertures 56 and 56′ are uncovered, escape of liquid through the sideapertures 56 and 56′ is reduced and/or prevented as the coating 64repels the liquid. In this way, the coating 64 reduces and/or preventsliquid leaking from the mouthpiece 18.

FIGS. 4A to 4E illustrate views of at least one example embodiment of anaerosol-generating device 10. The valve 26 is an ball valve. In at leastone example embodiment, a proximal end 16 of the mouthpiece 18 of thehousing 12 is covered by a valve connector 28. The valve connector 28has a distal open end 30 and a proximal closed end 32. The open end 30is shaped to slide over the proximal end 16 of the mouthpiece 18 and beretained in position covering the proximal end 16.

In at least one example embodiment, the closed end 32 includes anaperture 66. The aperture 66 is aligned with the air channel 25 of thedevice 10 as shown in the cut through views of FIGS. 4D and 4E. FIG. 4Bshows a perspective front view of a valve portion 68 to be positionedover the closed end 32 of the valve connector 28. FIG. 4C shows a sideview of the valve portion 68 alone.

The valve portion 68 includes a central ball element 70. The ballelement 70 has an upstream side 72 that is rounded. The ball element 70has a downstream side 74 that is flattened. Extending radially outwardsfrom opposing sides of the downstream side 74 of the ball element 70 arewing portions 76 and 76′. The wing portions 76 and 76′ are each formedof a bent planar sheet. The sheet is bent to form a ‘zig-zag’ shape whenviewed from the side in FIG. 4C.

In position, the wing portions 76 and 76′ abut the closed end 32 of thevalve connector 28 and the ball element 70 is positioned within theaperture 66. The ball element 70 blocks the aperture 66 and reducesand/or prevents liquid such as e-liquid or condensed aerosol fromescaping through the valve 26.

The wing portions 76 and 76′ are formed of a resilient material, such asrubber or elastomer material, such that the wing portions 76 and 76′ aredeformable. The ‘zig-zag’ shape of the wing portions 76 and 76′ allowthe wing portions 76 and 76′ to act like a spring. If the wing portions76 and 76′ are deformed by an applied force, the wing portions 76 and76′ will return to their original position when the force is removed.When air is drawn through the device 10, air pressure on the upstreamside 72 of the ball element 70 pushes the ball element 70 away from theaperture 66 and the wing portion 76 and 76′ deform. The ball element 70no longer covers the aperture 66 such that air can pass through thevalve 26.

The ball valve 52 includes an inner coating 78, shown in FIG. 4E. Theinner coating 78 is a hydrophobic coating. The coating 78 is located onthe upstream side 72 of the ball element 70. The coating 78 repelsliquid, such as e-liquid or condensed aerosol. When there is a draw onthe device 10, the ball element 70 is drawn away from the aperture 66,and escape of liquid through the aperture 66 is reduced and/or preventedas the coating 78 repels the liquid. In this way, the coating 78 reducesand/or prevents liquid leaking from the mouthpiece 18.

FIGS. 5A, 5B, and 5C illustrate the airflow channel through a consumableportion of an aerosol-generating device of the type shown in FIG. 1. Theconsumable portion comprises an outer housing 85 and an inner housing86. Within the inner housing 86 is a reservoir 22 having an outer wall82. The reservoir 22 holds an aerosol-forming substrate 80, such as aliquid aerosol-forming substrate. A mesh heater 84 is provided at thebase of the reservoir 22, which, in operation, vaporizes liquid from thereservoir 22. The vapor can escape into the airflow channel 90. Theairflow channel 90 extends from an inlet, through the housing to amouthpiece, including a valve as described.

The walls of the airflow channel 90 are provided with two differentmembranes in a layered structure, illustrated in FIG. 5B and FIG. 5C.FIG. 5C is an enlargement of a portion of FIG. 5B, in which the twolayers can most clearly be seen. The underlying layer 94 is ahydrophilic layer. The overlying layer 92, which is in contact with theaerosol in the airflow channel 90, is hydrophobic. This combination oflayers acts a diode for liquid flow, so that liquid condensed onto thehydrophobic layer is transported efficiently to the hydrophilic layerbut liquid does not pass from the hydrophobic layer back to hydrophiliclayer. If the outer wall of the reservoir is made fluid permeableunderneath these layers, for example by forming apertures through it, oris replaced entirely by these layers, then liquid condensing in theairflow channel downstream of the heater can be effectively returned tothe reservoir.

We claim:
 1. An aerosol-generating device, comprising: a housingincluding, a first end defining a mouthpiece, a second end, and a cavitybetween the first end and the second end; a reservoir within the cavity,the reservoir configured to store an aerosol-forming substrate; anatomizer; and a valve within the mouthpiece of the housing, the valvehaving a first side and a second side, the second side of the valveincluding a hydrophilic coating, a hydrophobic coating, or both ahydrophilic coating and a hydrophobic coating.
 2. The aerosol-generatingdevice according to claim 1, further comprising: an air inlet in thehousing; and an airflow channel extending from the air inlet, throughthe cavity, to the mouthpiece, and the valve in the airflow channel. 3.The aerosol-generating device according to claim 2, wherein the airflowchannel passes the atomizer.
 4. The aerosol-generating device accordingto claim 1, wherein the valve is a one-way valve, and the valve isconfigured to reduce the aerosol-forming substrate passing from thesecond side of the valve to the first side of the valve.
 5. Theaerosol-generating device according to claim 1, wherein: the valveincludes a hydrophobic coating; and the aerosol-generating devicefurther comprises, a storage tank configured to receive a portion of theaerosol-forming substrate repelled by the hydrophobic material of thecoating.
 6. The aerosol-generating device according to claim 1, whereinthe valve is a ball valve, a duckbill valve, a diaphragm, an umbrellavalve, or a hinged flap.
 7. The aerosol-generating device accordingclaim 1, wherein the valve is actuated via a draw on the mouthpiece ofthe aerosol-generating device.
 8. The aerosol-generating deviceaccording to claim 1, wherein the valve is actuated via a button on thehousing.
 9. The aerosol-generating device according to claim 1, whereinthe valve is at or near the first end of the housing and within themouthpiece.
 10. The aerosol-generating device according to claim 1,wherein the atomizer comprises a heater.
 11. The aerosol-generatingdevice according to claim 10, wherein the heater comprises at least oneheating element.
 12. The aerosol-generating device according to claim11, wherein the heater is in communication with a wick, and the wick isconfigured to direct the aerosol-forming substrate from the reservoir tothe at least one heating element.
 13. The aerosol-generating deviceaccording to claim 11, further comprising: a director configured todirect liquid resulting from condensation of aerosolized aerosol-formingsubstrate towards the at least one heating element.
 14. Theaerosol-generating device according to claim 1, wherein the reservoircomprises an outer wall including a first face exposed to an airflowchannel, the first face formed of hydrophobic material, and a secondface, opposite the first face, the second face formed of a hydrophilicmaterial.
 15. The aerosol-generating device according to claim 14,wherein the outer wall is in the airflow channel downstream of theatomizer.